Ditch the term pathogen

A short comment, published in the 11 December 2014 issue of Nature and entitled “Ditch the term pathogen,” is the most interesting, thought-provoking piece that I have ever read in that distinguished science magazine, and, over the years, I have read quite a few. The argument of the authors, Arturo Casadevall and Liise-anne Pirofski, is that the idea that diseases are caused by external agents—pathogens, bad microbes—is incorrect and part of an oversimplistic paradigm.

This paradigm, which can be associated with “germ theory,” has long been considered the triumph of “scientific medicine,” which took hold in the nineteenth century thanks to the work of such great scientists as Louis Pasteur and Robert Koch, and of Claude Bernard (1813-78), the founder of experimental physiology. Because it helps frame the medical and political discussions of the present piece, I will here call particular attention to one of Bernard’s best-known views: that the human body (and other living bodies), though it has need of its surrounding environment, is nevertheless relatively independent of it. Our tissues are separated from direct external influences and are protected from them (e.g. by our immune systems). Disease occurs when something bad enters our bodies from the outside and overwhelms our defenses.

With politics as well as medicine on my mind, I note that the pathogen or germ-theory paradigm may bring to mind George W. Bush and his (or his speechwriters’) axis of evil. In this paradigm, as in many of our ideas about health and sanitation, “I” or “we” (the United States) are basically good and pure, and so the danger is that we may be invaded or infected by evil, corruption, disease outside ourselves. To remain healthy, we have to build up our defenses and also attack our enemies, weakening their power to do us harm. Thus, for example, we use drones to try to kill “terrorists” (anti-US, non-state actors) in foreign countries. And we believe that if our espionage and screening procedures can identify dangerous external agents and their weapons, and do away with them before they, say, get on our airplanes, we will at least be able to travel safely.

A different paradigm is offered by the FBI’s COINTELPRO program and related FBI activities of the 1950s, 60s, and 70s. One of its techniques for combating Americans who were, for example, active in the Civil Rights and anti-Vietnam-War movements was to try to create and foster personal conflicts among activists and to arouse suspicions about their sexual and financial activities. As the human rights activist Aryeh Neier writes in a recent review of a book by former Washington Post reporter Betty Medsger, “the FBI sent ‘poison pen’ letters to break up marriages; there were incitements by the FBI to gang warfare; and members of a violent group were falsely [proclaimed to be] police informers.” From a somewhat medical perspective, we might say that the disease model here is that bad things happen when the “normal flora” within the organism become deranged or get out of control.

I note that this paradigm can apply whether you believe that Hoover was out of control or that, say, Martin Luther King Jr., the target of COINTELPRO’s most sustained campaign, was out of control. It is also important to note, however, that Hoover himself was working with a germ-theory paradigm: King, white Leftists, and American Indians were all outsiders, external agents, trying to destroy some otherwise healthy inside of white America. The paradigm of the Civil Rights and anti-war activists was that the organism itself was corrupt, with this corruption certainly linked to the foundation of the republic as a democracy that condoned slavery.

Clearly I am quite interested in political observations that Casadevall and Pirofski’s note may inspire, but I am also interested in the purely medical perspective, and this, and not politics, is the entire focus of the Nature piece. Thus the scientists—professors at the Albert Einstein College of Medicine at Yeshiva University in New York—first recognize that the pathogen paradigm has been associated with some of medicine’s great successes, for example the development of vaccines for tetanus and diphtheria. But, they write:

the use of the term pathogen sustains an unhelpful focus among researchers and clinicians that could be hindering the discovery of treatments. In the current Ebola epidemic in West Africa, for instance, much attention has been focused on the ill and the dead, even though crucial clues to curbing the outbreak may be found in those who remain healthy despite being exposed to the virus.

Instead of focusing on what microbes do or do not do, researchers should ask whether an interaction between a host and a microbe damages the host, and if so, how. . . .

Despite decades of searching, no classical virulence factor suitable for vaccine development has been identified for the tuberculosis bacillus or malaria parasite. Pulmonary tuberculosis occurs in less than 10% of the people infected with Mycobacterium tuberculosis. In these people, an over-exuberant inflammatory response destroys lung tissue. [In our post-Ferguson era, we might call this “over-policing.”]

I am reminded of a conversation I have been having with my teenage son, about how truth in science keeps changing. We are so often so sure that we have, thanks to hard work and genius, finally discovered “the truth” and relegated to the dark past our ancestors’ ignorance. And then, a few generations later, a new theory—e.g. germ theory—comes along, and seems to deliver the truth once and for all, until it, in turn, is supplanted.

May I be allowed a brief detour into Nietzsche’s Jenseits von Gut und Böse (Beyond Good and Evil), Section 31:

When the young soul, tortured by all kinds of disappointments, finally turns suspiciously against itself . . . how it tears itself to pieces, impatiently! how it takes revenge for its long self-delusion, just as if it had been a deliberate blindness! In this transition . . . above all one takes sides, takes sides on principle, against “youth.” — Then years later one comprehends that all this, too, was still youth.

We come back again to medicine, as to our touchstone, and noting that Plato’s Socrates invariably used medicine as his starting point for explorations of justice and “the good.” Germ theory has given us the idea that, to keep from getting infected and sick, we should often wash our hands or use anti-microbial products. And certainly there is evidence that hand-washing can help prevent disease. But there is also a theory that children these days are more prone to allergies and other maladies because of their lack of exposure to external agents, because they don’t play in the dirt anymore. And medicine has been exploring treatments that involve putting alien fecal matter into sick people in order to give them the microbes they need to be healthy. Casadevall and Pirofski speak of the “host-microbe” interaction, which can lead to flourishing or disease. What is important, we might say, is not opposed things—us and them, microbes and hosts—but relationships, systems. (A leitmotif of the present essay: our science is ever in dialogue with our times, our social and economic lives. In the industrial age, the nineteenth century, there were inputs and outputs; now we have service-based economies and the Web; we see the importance of relationships, computer systems, social networks.)

From a political perspective we may be led, by analogy, to conclude that it matters less who they are and who we are, and more what kinds of relationships we are able to enter into. (Though this, of course, is a function of who we both are.) And we may see here, too, the walls between them and us breaking down. Instead of attacking and defending, we may see how we are, inevitably, intermingling. We might think about successful and unsuccessful interminglings.

Almost finally, and with George W. Bush again in mind, I would note that, although this is not a focus of Casadevall and Pirofski’s “Ditch the term pathogen,” that piece does touch on the matter of identity. Or what I am headed toward saying is that the whole host-microbe paradigm may be outmoded if not wrong. It has been said, for example, that in a human body, microorganisms—thousands of different kinds of bacteria, fungi, and archaea—outnumber human cells 10 to 1. Apparently the majority of these organisms have been too poorly researched for us to understand the roles they play. However, communities of microflora have been shown to change their behavior in diseased individuals. The once “normal flora” begin causing problems.

This, we might say, is the greater fear of states or of their governments. Not that some fringe group will become enraged and violently act out; such behavior only strengthens the power of the state and of its police. (And Hoover is hardly the only law-enforcement official—in the United States, Russia, and elsewhere—who has sought to promote violence in order to increase his own power and capacities for repression.) But things fall apart when the normal flora—the Third Estate in revolutionary France; US college students during the 1960s—are at war with the organism of which they are an integral part. (In a documentary about the Free Speech Movement at the University of California, Berkeley, one of the students remarks that he and his fellow protesters—students at an elite university—had been supposed to become the managers of the system, of its major corporations and government agencies. But now they were its most outspoken opponents.)

A state cannot survive without soldiers and police willing to shoot, teachers eager to indoctrinate, and food deliverers, health-care providers, and religious leaders willing to nurture, comfort, and restore. So, too, a body cannot survive without, among other things, its bacteria, fungi, and archaea. And thus it seems wrong to imagine, as we do, that some microorganism-less “I” exists, has meaning. A hotel without guests is not a hotel. And perhaps a state whose army and borders are too strong—and too impervious to alien ideas—cannot long survive. And similarly for hegemonic economic systems (capitalism now) or religious institutions (the Roman Catholic Church of the Middle Ages).

Though not wishing to wander too far from this piece’s original tangle, I would nonetheless recall a point that has been made in other contexts: an “us” cannot exist without a “them.” Our ideas of health depend on our ideas of disease; our ideas of what is external on our ideas of what is internal, integral. Freud notes in Das Unbehagen in der Kultur (Civilization and its Discontents) that the apostle Paul’s idea of universal love as the foundation of a Christian community necessitated the extreme intolerance of this community—its savage attacks on outsiders. But we are back to something like germ theory here; Freud’s perspective was a product of the nineteenth century. A point that might be made now would be that wars within Paul’s own psyche—as within J. Edgar Hoover’s and many, many another’s psyches—are what led to the hatefulness, and to a reduction of the world into a war between good and evil, and to the positing of the possibility of a good within threatened by the evil without.

In medicine, politics, and psychology, we have had this idea that there is some “I,” the host, who has an integrity and purity, and who is threatened and perhaps invaded and occupied by alien bacteria or bacteria-like agents, which may be helpful (undocumented alien cleaning ladies, nannies, and nurses) or noxious (ISIS, Al-Qaeda). In some religions there is even an idea that the “I” may be born corrupt, and so one of its fundamental struggles is to achieve purity, by driving out the bad parts of itself. Such thinking helped “inform” and make effective the propaganda that led to the Holocaust. Jews, Leftists, trade-unionists, homosexuals, gypsies were labelled as evils within, and it was proposed that goodness and purity could be achieved by extirpating them: killing them.

This was of course worse than vicious propaganda, but my point here is that it was also bad “science,” in the sense that current circumstances (our technology and economic systems included) are calling our attention to the fact that there is no purity within; there is no “I” and them, no “us” and them. There is a collection of different entities that can and do relate in a range of ways, some of which are considered beneficial to the collection as a whole, and some of which are considered noxious.

The Huron and Seneca Indians apparently believed that our souls have desires quite beyond our conscious wishes and that these desires are made known to us through dreams. If we subsequently fulfill these desires, our souls are satisfied, but if we fail or ignore the desires, our souls may become angry and may revolt against our bodies, causing various diseases and even death. In the short poem “Harlem,” Langston Hughes famously suggested that if our dreams and desires were “deferred”—for example, because of racism, economic oppression, and poor educational systems—the result could be desiccation, rot, festering sores, a fundamental falseness, depression, or violence.

Casadevall and Pirofski write that Escherichia coli (E. coli) is “one of the many species in the human gut,” and that as a rule these bacteria cause no harm. Indeed, the traditional view is that these bacteria prevent the colonization of the intestine with pathogenic bacteria. But E. coli can also cause diarrhea and vomiting.

It is hard this week to write without making reference to the killing of the journalists at Charlie Hebdo in Paris. In closing, and leaning on Casadevall and Pirofski’s excellent scientific comment, I would simply say again: we might do well to ditch the term pathogen, along with any axis of evil, and focus more attention on our interminglings—when do they seem to work, and when not?

Credits and Links

Cartoon above is by Thom J. Tailor (writer) and Ookah (cartoonist). They have an online comic strip, Drink a lol. A loose translation of the text:

Boy: “When I grow up, I’m going to be an editorial cartoonist.”

The Grim Reaper: “You must not be following the news, little boy.”

Boy: “No, I am.”

The lead photo is of J. Edgar Hoover, from the Associated Press.

Colorful photo is by Stephanie Schuller. The caption begins: “E. coli bacteria. Coloured scanning electron micrograph (SEM) of Escherichia coli bacteria (green) taken from the small intestine of a child.” Click to see more of Schuller’s work.

1 reply

Forgive an esprit simpliste from observing that using medicine as your metaphoric touchstone may complicate more than it clarifies, leading to a kaleidoscope of shifting speculations. Perhaps that’s because you are a philosopher. You and Jonah do concede that truth in science is always changing. But it also changes depending on which “dis-ease” we are looking at. “Ditching the pathogen concept” (while helpful) is only a first and incomplete step towards understanding the many kinds of interminglings that may bring us into a better state of health, whether of our personal bodies or our bodies politic.

Surviving the Twenty-First Century

What is This?

Now with 1,900 followers, anglophones et francophones, spanning the globe. (The author is pleased, too, to have made a Best Essays list of Notable Essayists.)

Meanwhile, this collection of short and longer essays, aphorisms, poems and quotations continues to expand. From another dear reader: “I am constantly waiting for new posts because your work is quite amazing.”